Chip-packaging with bonding options having a plurality of package substrates

ABSTRACT

Chip-packaging with bonding options having a plurality of package substrates. The chip-packaging includes first and second package substrates, a chip, and a lead. The chip having a plurality of bonding pads is mounted on the first package substrate. One of these bonding pads is connected to the first package substrate. Another bonding pad is connected to the second package substrate. The lead is connected to one bonding pad. The first and second package substrates have first and second voltages, respectfully. The first voltage and the second voltage are different, and each can be a GND voltage or a POWER voltage. With connection of these bonding pads with the lead or connection of these bonding pads with two package substrates, input ends or output ends in the chip could be connected to a GND voltage or a POWER voltage, or to one pin of the chip-packaging.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to a chip-packaging, and moreparticularly, to a chip-packaging with bonding options having aplurality of package substrates.

2. Description of the Prior Art

In the modern VLSI circuit design, circuits in a package are connectedto an outside power supply or other devices by a bonding mechanism.Therefore, allocations of bonding pads and methods of bonding optionsare basic and important technologies. In general, there are manydifferent functions in one circuit, and there are many pinscorresponding to the different functions in a circuit package. However,not all functions of the circuit are used, so some pins in the circuitpackage are connected to the outside circuits while others are not.Thus, some pins called Enable and Disable are provided. Pins having thefunction of Enable mean that when the pins are given a fixed highvoltage (usually the voltage of the power supply), some functionscorresponding to these pins in the chip are enabled. Similarly, pinshaving the function of Disable mean that some functions of the chip aredisabled when the pins are given a fixed low voltage (usually the GNDvoltage). The Enable pins and the Disable pins allow make users to beable to choose the different functions of the chip so as to increaseefficiency of the chip.

The method of providing a bonding option is used to provide Enable,Disable, and Input/Output options for some pins of a package. Thismethod not only allows users to change the hardware configuration ofVLSI circuits, but also to provide detecting and debugging of the VLSIcircuits.

In the prior art, one bonding option usually comprises a plurality ofbonding pads. These bonding pads provide different bonding choices. Forexample, a bonding pad can be connected to a high voltage pin (supplyvoltage) or a low voltage pin (ground). Previous architectures of thebonding options include two types: the value-default type and thepower/ground proximity type. Please refer to FIG. 1 and FIG. 2. FIG. 1and FIG. 2 illustrate an architecture of the bonding option of thevalue-default type. In the architecture, each bonding pad has isconnected to a logic “1” of a high voltage or a logic “0” of a lowvoltage in the bonding option circuitry. If there is not any inputsignal applied to the pin of the bonding pad, the voltage of the pinwill maintain a default voltage, which depends on what the pin isconnected to. For example, the default voltage is high voltage “1” inthe bonding option of the value-default type of FIG. 1. If the voltageof the pin is not defined by an outside system, the pin has logic “1”.On the other hand, the default voltage is low voltage “0” in the bondingoption of the value-default type of FIG. 2, and thus if the voltage ofthe pin is not defined by an outside system, the pin has logic “0”.

Here we further state the principle of operations in FIG. 1 and FIG. 2.Please refer to FIG. 1. The bonding option device 12 of thevalue-default type in FIG. 1 comprises a passive circuit 10. The passivecircuit 10 that is connected to POWER and the power supply consists of aPMOS. The passive circuit 10 has small resistance so that it has reallyhigh conductivity. When the passive circuit 10 turns on, the voltagedrop between the drain and the source of the PMOS is almost zero.Therefore, POWER is set to the voltage of the power supply. In otherwords, when POWER is not input by outside signals, the passive circuit10 turns on and POWER increases to a high voltage so that the insidecircuitry will receive a signal of logic “1” from the bonding pad.

Please refer to FIG. 2. The bonding option device 16 of thevalue-default type FIG. 2 comprises a passive circuit 14. The passivecircuit 10 that is connected to GND and the ground consists of a NMOS.The passive circuit 14 also has small resistance so that it hasconsiderably high conductivity. When the passive circuit 14 turns on,the voltage drop between the drain and the source of the NMOS is almostzero. Therefore, GND is set to the voltage of the ground. Say, when GNDis not applied by outside signals, the passive circuit 14 turns on andGND is forced to a low voltage so that the inside circuitry will receivea signal of logic “0” from the bonding pad.

However, the architecture has undesirable disadvantages. If one bondingpad of the architecture is applied by an input signal from an outsidesystem and the input signal is different from the default voltage, itleads to additional power consumption. This disadvantage is serious inthe modern electronic devices of small sizes.

Please refer to FIG. 3. FIG. 3 illustrates the well-known architecture17 of the bonding option of the power/ground proximity type. Thearchitecture comprises a plurality of bonding pads, and each bonding padis adjacent to a POWER and a GND. These bonding pads do not have adefault voltage. If one bonding pad must be connected to logic “1”, thebonding pad is connected to POWER in FIG. 3. If one bonding pad must beconnected to logic “0”, the bonding pad is connected to GND. Thearchitecture not only provides logic “1” or “0” for bonding pads butalso avoids power waste. However, as described before, each bonding padneeds two connection points, POWER and GND for bonding choices, so theseconnection points and each bonding pad should be specially arranged. Inthe case of a chip with many pins, arrangement of the bonding padsbecomes very troublesome.

SUMMARY OF INVENTION

It is therefore a primary objective of the claimed invention to providea chip-packaging to solve the above-mentioned problems.

According to the claimed invention, a chip-packaging with bondingoptions having a plurality of package substrates comprises a firstpackage substrate, a second package substrate, a chip comprising aplurality of the bonding pads and mounted on first package substratewherein one bonding pad is connected to the first package substrate andanother bonding pad is connected to the second package substrate, and alead connected to one bonding pad.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an architecture of the bonding option of thevalue-default type.

FIG. 2 illustrates an architecture of the bonding option of thevalue-default type.

FIG. 3 illustrates the architecture of the bonding option of thepower/ground proximity type according to the prior art.

FIG. 4 illustrates the bonding option architecture providing threeconnection points for the bonding pads according to the presentinvention.

FIG. 5 illustrates the bonding option architecture of the presentinvention.

FIG. 6 illustrates another bonding option architecture.

FIG. 7 is a cross-sectional view of the option architecture of FIG. 4.

FIG. 8 is a cross-sectional view of the option architecture of FIG. 6.

DETAILED DESCRIPTION

As mentioned in the prior art, usually one bonding option unit of a chiphas to connect to three possible connection points: the ground, thepower supply, and the bonding option. Because one chip often hasdifferent functions or configurations, some pins of the chip must bedefined their voltage as Enable or Disable. Enable represents the highvoltage of logic “1”(the power supply). If one pin of the chip isconnected to the power supply, some function of the chip is enabled. Incontrast, Disable represents the low voltage of logic “0”(the ground).If one pin of the chip is connected to the ground, some function of thechip is disabled. Application of Enable and Disable provides functionselections of a chip and can be used as “1” or “0” of the testingsignals.

Please refer to FIG. 4. FIG. 4 illustrates the bonding optionarchitecture 50 of the present invention providing three connectionpoints for the bonding pads. The bonding option architecture 50comprises a plurality of leads 52, a plurality of bonding wires 54, achip 56, a first package substrate 58, and a second package substrate60. The chip 56 comprises a plurality of bonding pads 62. The bondingpads 62 are set inside the chip 56 and surround the chip 56, providingthe outlets of input/output ends of the chip 56. The leads 52distributed around and outside the chip 56 are connected to the bondingpads 62 inside the chip 56 through bonding wires 54. The bonding pads 62are like the connection points which connect the inside circuit of thechip 56 to the outside system while the leads 52 are like the connectionpoints which connect the outside system to inside circuit of the chip56. The bonding option architecture 50 lets the input/output signals ofthe chip communicate with outside circuitry and provides chip testing.

The first package substrate 58 and the second package substrate 60 arethe bottom plates of the chip package. The shape of the packagesubstrate is shown in FIG. 4. The chip 56 is mounted above the secondpackage substrate 60, which the first package substrate 58 immediatelysurrounds. The outside periphery is the second package substrate whichalso surrounds the first package substrate. In this arrangement ofpackage substrates, one can see at least one portion of the firstpackage substrate 58 and at least one portion of the second packagesubstrate 60 when looking outside from the chip in any direction. Inother words, any bonding pad 62 approximates at least a portion of thefirst package substrate 58 and at least a portion of the second packagesubstrate 60. Because a plurality of the leads 52 are distributed aroundthe chip, the bonding pad 62 also approximates at least one lead. Twopackage substrates are used here for providing two different voltages tothe bonding option, wherein one package substrate has a high voltage andthe other has a low voltage. For example, the first package substrate 58is applied to the power supply and the second package substrate 60 isapplied to the ground voltage.

Please refer to FIG. 7. FIG. 7 is a cross-sectional view of the optionarchitecture 50 of FIG. 4. The chip 56 is shown mounted on the secondpackage substrate 60, and the first package substrate 58 is formed inbetween sections of the second package substrate 60. The chip 56contains the plurality of bonding pads 62 around the perimeter of thechip 56, and the leads 52 are formed around the perimeter of the secondpackage substrate 60.

Please refer to FIG. 5. FIG. 5 illustrates the bonding optionarchitecture of the present invention. The bonding option architecturein FIG. 5 is the detailed illustration of FIG. 4. Each marked item inFIG. 5 of the same names with those in FIG. 4 has the same functions.Besides, FIG. 5. further shows a bonding option unit 80. The bondingoption unit 80 is connected to the inside circuitry of the chip 56, andthe bonding pad 62 is included in the bonding option unit 80. Asmentioned before, the bonding option unit 80 is possibly connected toEnable, Disable, or to the other systems. Therefore, there are threeconnection points: the lead 52 for the first bonding option, the firstpackage substrate 60 for the second bonding option, and the secondpackage substrate 58 for the third bonding option near the bonding pad62. The first bonding option provides outlets for input/output signalsof the chip 56. The second bonding option and the third bonding optionprovide the voltage of the power supply and the voltage of the ground.In the preferred embodiment of the present invention, the first packagesubstrate 58 serving as the second bonding option provides the powersupply while the second package substrate 60 serving as the thirdbonding option provides the ground. Of course, the voltages that twopackage substrates have can be exchanged. In this embodiment, when thebonding option unit 80 needs a voltage of the power supply, the bondingwire 54 connects the bonding pad 62 to the first package substrate 58 sothat the voltage of the power supply is applied to the bonding optionunit 80 and reaches the inside circuitry. In another case, when thebonding option unit 80 has to be connected to the ground, the bondingwire 54 connects the bonding pad 62 to the second package substrate 60so that the bonding option unit 80 has the ground voltage. In the lastcase, the bonding option unit 80 is connected to the lead 52 through thebonding wire 54 for generating a transmission trace between the insidechip and the outside systems. Thus, the present invention utilizes onlyone lead to provide three functions of a bonding option, which not onlyremoves the disadvantages of difficult arrangement of many leads in theprior art, but also lowers the production cost by reducing the number ofleads.

Notice that the embodiment in FIG. 5 sets up a single lead 52 for eachbonding option unit 80. In fact, the present invention can beimplemented using only one lead for a bonding option. However, thenumber of leads for a single bonding option unit 80 is not limited toone. Designers are free to set up any amounts of leads for one bondingoption unit for some special purpose. Moreover, the preferred embodimentof the present invention utilizes two package substrates. In reality, aplurality of package substrates can be provided for the bonding option.Change of the number of the leads for each bonding unit or the number ofthe package substrates is included in the claimed range of the presentinvention if they reach the similar effects of the present invention.

Please refer to FIG. 6. FIG. 6 illustrates another bonding optionarchitecture 100. In this embodiment, the shape of the package substrateis modified. The bonding option architecture 100 comprises a firstpackage substrate 90, a second package substrate 92, a chip 94, aplurality of the bonding pads 96, and a plurality of leads 98. The shapeof the first package substrate 90 is different from that in FIG. 4. Thechip 94 is mounted on the first package substrate 90. The area of thefirst package substrate 90 is larger than that of the chip 94, and thefirst package substrate 90 extends outside the chip 94 so that the firstpackage substrate 90 has enough area for a bonding wire to connect to.The second package substrate 92 surrounds the first package substrate90, and a plurality of the leads 98 are set on the periphery of thepackage substrate. In the bonding option architecture in FIG. 6, eachbonding pad 96 distributed around the chip 94 approximates threeportions, which are the first package substrate 90, the second packagesubstrate 92, and a lead 98. The three portions can be used as threeconnection points: the first bonding option, the second bonding option,and the third bonding option, for the bonding pad 96. The first packagesubstrate and the second package substrate are connected to twodifferent voltages, the power supply and the ground. The lead 98 servesas input/output outlets. Therefore, this embodiment implements functionsof the bonding options. Of course, the package substrate has otherchanges in shapes, which is also included in the present invention.

Please refer to FIG. 8. FIG. 8 is a cross-sectional view of the optionarchitecture 100 of FIG. 6. The chip 94 is shown mounted on the firstpackage substrate 90, and the second package substrate 92 surrounds thefirst package substrate 90. The chip 94 contains the plurality ofbonding pads 96 around the perimeter of the chip 94, and the leads 98are formed around the perimeter of the second package substrate 92.

In the bonding option of the value-default type of the prior art, if onebonding pad of the architecture is applied by an input signal from anoutside system and the input signal is different from the defaultvoltage, it leads to additional power consumption. It is an unacceptabledisadvantage in the modern electronic technology of low power. On otherhand, the bonding option of the power/ground proximity type in the priorart, though, removes the problem of additional power consumption. In thecase of a chip having many pins, arrangement of the bonding pads becomesa big trouble because the connection points and each bonding pad shouldbe specially arranged. Moreover, due to the large area of the bodingpads, if the number of the bonding pads is large, the chip area will beunnecessarily increased using the bonding option of the power/groundproximity type, raising the production cost.

Compared to the prior art, the present invention utilizes a plurality ofpackage substrates as the voltage supply or the ground to implementbonding option without increasing additional leads. Therefore, thepresent invention has the following advantages: 1. Provide convenienttesting and other functions for a chip, and let a single chip operate indifferent modes. 2. Make it easier to arrange leads because only onelead is needed for providing the voltage of the power supply and theground. 3. It is easier to use and maintain the bonding option. 4. Lessnumber of leads to smaller layout area and lower production cost. Thepresent invention reserves the advantages of the prior art and hasadditional advantages that the prior art cannot achieve.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device may be made while retainingthe teachings of the invention. Accordingly, the above disclosure shouldbe construed as limited only by the metes and bounds of the appendedclaims.

1. A chip-packaging with bonding options having a plurality of packagesubstrates, comprising: a first package substrate having a high voltageor a low voltage; a second package substrate having a high voltage or alow voltage, the voltage level of the first package substrate being thelogical opposite of the voltage level of the second package substrate;and a chip mounted on first package substrate, the chip comprising aplurality of bonding option pads, wherein each bonding option pad of thechip is associated with at least two bonding options respectivelyprovided by the first package substrate and the second packagesubstrate, and each bonding option pad is connected to one of the firstpackage substrate and the second package substrate.
 2. Thechip-packaging of the claim 1 wherein the high voltage is the voltage ofthe power supply and the low voltage is the ground voltage.
 3. Thechip-packaging of the claim 1 further comprising a plurality of leads,wherein each lead is connected to a high voltage, a low voltage, or aninput/output signal.
 4. The chip-packaging of the claim 1 wherein thefirst package substrate extends outside the chip and the second packagesubstrate surrounds the chip.
 5. The chip-packaging of the claim 1wherein the first package substrate and the second package substratesubstantially approximate each of a plurality of the bonding optionpads.
 6. The chip-packaging of the claim 1 further comprising aplurality of leads, each bonding option pad of the chip having acorresponding lead, wherein each bonding option pad is connected to oneof the first package substrate, the second package substrate, and thecorresponding lead.
 7. The chip-packaging of the claim 1 wherein eachbonding option pad is connected to one of the first package substrateand the second package substrate for determining the functionality ofthe chip.